1. Field of the Invention
The present invention relates to a data backup method for a server, and more particularly, to a storage service device with a dual controller and a backup method thereof.
2. Related Art
In order to enhance the access performance of a storage device, a storage service device with a dual controller has been proposed. Compared with the configuration of a single controller, the dual controller can provide the same service to a plurality of clients at the same time.
In the past, in order to ensure that a plurality of clients has the same operation environment, the dual-controller storage service device employs the same view function. The same view function mainly aims at preventing the clients from having different operation environments and services due to the different controllers adopted for the provided services when the clients are connected to the storage device. For example, when the system has created a virtual disk in a first controller, if another client is connected to the storage service device through a second controller, the client can also see the virtual disk.
In addition to the same view function, a “mirror cache” function is also proposed, so as to enable the dual controller to ensure the data synchronization in the dual controller when accessing data. The mirror cache means to configure a respective cache in each controller. Thus, when a first controller receives/retrieves data, it may copy the data stored temporarily in the cache thereof into a cache of a second controller, thereby ensuring that the two controllers have consistent data. Moreover, when an error occurs to one of the two controllers, the storage service device can recover the lost data from the cache of the other controller.
In order to maintain the consistency between the index pages of the two controllers, configuration files and login files are stored in a flash memory or a hard disk in the prior art. Although the storage purpose can be effectively achieved, it takes risks in terms of the storage security. Taking the flash memory for example, due to the limited accessing times for the flash memory, once the flash memory is damaged, the entire system may be crashed due to the loss of relevant data. Taking the hard disk for example, because the hard disk belongs to a mechanical access mode, the hard disk cannot be moved while performing motions; otherwise, the hard disk is easily destroyed.